Touch panels are a particular class of electronic visual displays, which are able to detect and locate a touch within a display area. Generally, touch panels include a transparent body disposed over a screen and configured to sense a touch. Such a body is substantially transparent, so that light in the visible spectrum emitted by the screen can be transmitted therethrough. At least some known touch panels include a transparent body constituted by a barrier and a transparent conductor formed, in this order, over a substrate. A touch on the display area of such a panel generally results in a measurable change of capacitance in a region of the transparent body. The change in capacitance may be measured using different technologies, so that the position of the touch can be determined.
A transparent body for use with a touch panel is subject to some particular requirements. In particular, one key requirement is that the transparent body is stable enough for withstanding multiple contacts on the screen and harsh conditions, so that reliability of the touch screen is not compromised over time. However, at least some known transparent bodies included in touch screens which are considered robust interfere with a proper transmission of light therethrough due to, for example, thickness, composition, and structure of the layers forming the transparent body. Furthermore, fabricating such a stable transparent body with high quality, for example with a uniform and defect-free barrier, is challenging.
Accordingly, it is desirable a process and an apparatus for forming a high-quality transparent body for use in a touch panel in a manner such that the body is stably formed over the substrate without compromising a proper transmission of light in the visible spectrum.
Further, a common manufacturing process for touch panel applications can be a sputtering process, wherein a touch panel coating is deposited on a plastic film using roll-to-roll sputter web coater. There are several types of touch panel coatings on the market. Typically, when changing from one touch panel process to the next process a change of sputter target(s) or cathode(s) is conducted. Thereby, the machine is vented and opened. The sputter target(s) are removed and replaced by a different target material. This procedure is time consuming and can create failures (e.g. a water leak). Accordingly, there is a further desire to improve the cost of ownership for the operator of a touch panel manufacturing system and provide additional value.